Warp knit fabric containing loose filling and having unfrayed selvage and method and apparatus for making the same



Nov. 24, 1970 SHARPE 3,541,812

WARP KNIT FABRIC CONTAINING LOOSE FILLING AND HAVING UNFRAYED SELVAGEAND METHOD AND APPARATUS FOR MAKING THE SAME Original Filed Sept. 7,1967 5 Sheets-Sheet 1 ATTORNEY-S Nov. 24, 1970 N. K. SHARPE $541,812

WARP KNIT FABRIC CONTAINING LOOSE FILLING AND HAVING UNFRAYED SELVAGEAND METHOD AND APPARATUS FOR MAKING THE SAME Original Filed Sept. 7,1967 5 Sheets-Sheet 2 my 0 H Q mf'i U INVENTOR Nov, 24, 1970 N. K.SHARPE 3,541,812

WARP KNIT FABRIC CONTAINING LOOSE FILLING AND HAVING UNFRAYED SELVAGEAND METHOD AND APPARATUS FOR MAKING THE SAME Original Filed Sept. 7,1967 5 Sheets-Sheet 5 INVENTOR A4517 1 52 95 5 ATTORNEYS Nov. 24, 1970SHARPE 3,541,812

WARP KNIT FABRIC CONTAINING LOOSE FILLING AND HAVING UNFRAYED SELVAGEAND METHOD AND APPARATUS FOR MAKING THE SAME Original Filed Sept. 7,1967 5 Sheets-Sheet 4 F/y7 /Zf 5/ v l i INVENTOR 2W A t-y K 66 4/62 5ATTOR NL-YS Nov. 24, 1970 N. K. SHARPE 3,541,812

WARP KNIT FABRIC CONTAINING LOOSE FILLING AND HAVING UNFRAYED SELVAGEAND METHOD AND APPARATUS FOR MAKING THE SAME Original Filed Sept. '7,1967 5 Sheets-Sheet s INVENTOR United States Patent ()1 ice 3,541,812Patented Nov. 24, 1970 3,541,812 WARP KNIT FABRIC CONTAINING LOOSE FILL-ING AND HAVING UNFRAYED SELVAGE AND E EM'I'EOD AND APPARATUS FOR MAKINGTHE Ned K. Sharpe, Greensboro, N.C., assignor to Burlington Industries,Inc., Greensboro, N.C., a corporation of Delaware Original applicationSept. 7, 1967, Ser. No. 666,057. Divided and this application Oct. 29,1968, Ser. No. 794,816

Int. Cl. D04b 23/10 U.S. Cl. 6685 This is a division of my copendingapplication, Ser. No. 666,057, filed Sept. 7, 1967, now US. Pat.3,444,707.

The present invention relates to a fabric and apparatus and method formaking a fabric. More specifically, it pertains to a kind of fabrichaving loose fibers or filling yarn laid in and bound together withinterlocking chain stitches produced by warp knitting. Each chain ofstitches is made from yarn which alternately forms stitches in adjacentrows.

For purposes of simplicity, the term sewing will be used herein to referto the warp knitting operation. This term has found use in the textileindustry in connection with this kind of fabric and avoids confusionbecause the word warp is used to refer to another yarn sometimes used inthis type of fabric, as will be explained below. Similarly, forconvenience, the threads which form these loops are referred to assewing thread.

Fabrics of this type can be made by forming a plurality of chainstitched rows of loops of sewing thread along an array of loose fibersor loose filling yarn. The stitches pass through the material at spacedpoints along the machine direction of the fabric and gather the fillingyarn, and to a certain extent the loose fibers, into a plurality ofclusters separated by spaces corresponding to the stitch insertionpoints. A plurality of stitches are formed simultaneously across thematerial, so that the spaces tend to be essentially continuous acrossthe fabric, especially where yarns are used as the filling.

The present invention is concerned with one kind of this class offabrics, in which the stitches of adjacent chains are interlocked, thatis a tricot stitch. This effect is obtained by the manner in which thesewing thread is supplied to loop forming needles. The thread passthrough guides which oscillate between adjacent needles. Each sewingthread end is alternately supplied to adjacent sewing needles, and eachchain contains loops alternately formed from two different threads.

This type of stitch has several advantages. First, the interknitting ofthe two sewing ends increases the durability of the fabric. If simplechain stitching is used, one break in a sewing thread may result in anentire chain of loops being pulled out. In the interlocking stitchdescribed above, each sewing thread is interlocked with two others;therefore, a broken thread will be held by two others.

Another advantage of this type of stitch is that it facilitates the useof warp yarns. It is known that dimensional stability of the fabric canbe improved by laying warp yarns against one side of the fillingmaterial and fastening them down with sewing thread. In the interlockingstitch, zigzagging of sewing thread between adjacent chains of loopsprovides a convenient means for holding the warp yarn in place. The warpyarn is simply laid against the fabric before the sewing thread is movedover it by the sewing thread guide.

However, the interlocking chain stitch has an important disadvantage.That is, it results in loose threads at the sides of the fabric and arough or irregular edge. This can best be understood by firstconsidering the simple 5 Claims chain stitch. With that type of stitch,the loose filling yarns are held in clusters by the sewing thread asexplained above. On one side of the filling, there is a loop for eachstitch, and, on the other side of the filling, there is the sewingthread connecting between adjacent loops. Whereas the connecting threadZigzags between adjacent chains in the interlocking chain stitch, in thesimple chain stitch it follows the same line as the loops. Therefore, atthe edge of the simple chain-stitched fabric, the clusters of loosefilling yarns are held together between the loops on one side and theconnecting threads on the other side. By cutting the filling close tothe last chain of loops, a neat unfrayed edge can be produced.

This cannot be accomplished in the warp knitting machines which employthe interlocking stitch. In this type of machine, at the edge of thefabric, two sewing threads form loops in the last chain. The first ofthese also is formed into loops in the next to the last chain. Thesecond is used in alternate loops in the last chain. However, when thefirst thread is transferred to the needle which produces the last chainof loops, the second thread is transferred to the needle which is beyondthe last chain. The second thread is formed into a loop by that needle,and then transferred back to the needle which forms the last chain, intime for the next stitch. Since this next needle is not supplied withsewing thread to form a next stitch, the loop that it has just formedremains loose. Ultimately, it will pull out, leaving loose thread in thelast chain of stitches.

This construction has several disadvantages. First, the loose thread inthe last chain can result in loosening the entire chain, and is easilysnagged. Second, the loose filling fibers or yarn are not properly heldin clusters and give the edge a frayed appearance. Any attempt to trimthe fabric close to the last chain of stitches will still leave thefilling loose in each cluster.

It might seem possible to simply remove the next needle so that looseloops will not be formed. However, this is not convenient. For example,needles usually are supplied in sets of, say, ten, mounted on a singlelead. It would be very difficult to provide independent mounting of theneedles unless they are spaced too far apart. Since a machine is used toproduce a variety of widths of fabrics, it is supplied with needle setsacross its full width, and the width of the fabric produced isdetermined by the number of sewing threads supplied. Therefore, removingthe next needle would require limiting the variety of fabric widths tothat corresponding to a number of needle sets, or modifying needle setsby removing individual needles. Neither is satisfactory.

A principal object of the present invention is to provide a fabric whichavoids the abovedescribed difliculty. Other objects are to provide amethod of producing such a fabric and apparatus for carrying out themethod.

In accordance with the present invention, the loose loops describedabove are pulled out before the sewing thread which forms them completesformation of another loop. Therefore, this sewing thread forms alternateloops in the last chain; the portion of that thread connecting betweenloops follows the chain of loops similar to the thread in simple chainstitching. This thread, then, tightly binds the clusters of loosefilling along a straight line. If the fabric is sheared close to thisline, it will have a neat, unfrayed edge.

Briefly stated, in accordance with a preferred embodiment, theabove-described loose loop is pulled out by a resilient thread guidewhose resilience is overcome by yarn tension when the loose loop isformed, but which recovers as soon as the loop is cast off a needle,thereby pulling the loop open.

As used herein, the term resilient is intended to de 3 scribed a memberpossessing resilience. The term resilience, for'pr'es'ent purposes,refers to the ability of a body to recover its size and shape afterbeing deformed, by stretching, compression or the like. Therefore, theterm resilient thread guide refers to a member in contact with thethread which is displaced when a loop is formed in that thread but whichresumes its original position when the loop is cast off.

Various types of material can be formed into a fabric by sewing inaccordance with the present invention. One preferred form of material isdescribed in US. Pat. 2,890,579. A plurality of loose filling yarns areprovided from continuous yarns which are wound back and forth across akind of tenter frame by a carriage, and around heddle hooks on movingconveyor belts at either side of the frame. The conveyors are movingwhile the carriage traverses the space between them, so that the fillingthreads are more or less oblique to the machine direction and in twosets which are oblique to each other. That is after a set of parallelthreads are caught on the hooks of one of the conveyors, the carriagemoves directly across to the other conveyor. While the carriage movesacross, the conveyors are moving perpendicularly to the carriage and, bythe time the carriage reaches the other conveyor, that other conveyorhas moved a short distance. Therefore the heddle hooks on which thethreads are caught on the second conveyor are not directly opposite thehooks used on the first conveyor, and the threads are oblique to themachine direction. When the carriage returns to the first conveyor, anopposite effect is observed, and the threads laid down are oblique tothe machine direction and to the threads laid down in the previoustraverse.

Substantially any textile fibers can be used for the warp, fillingand/or sewing thread. These include natural fibers such as cotton, wool,sisal, linen, jute and silk, man-made fibers and filaments such asregenerated cel lulose rayon, polynosic rayon, cellulose esters, e.g.cel lulose acetate, cellulose acetate/butyrate and cellulose triacetateand synthetic fibers and filaments such as acrylics,

e.g. polyacrylonitrile, modacrylics such as acrylonitrilevinyl chloridecopolymers, polyamides e.g. polyhexamethylene adipamide (nylon 66),polycaproamide (nylon 6) and polyundecanoarnide (nylon 11),polyolefin,e.g. polyethylene and polypropylene, polyester, e.g.polyethylene terephthalate, rubber and synthetic rubber, saran, glass,and the like. Sewing yarn sizes ordinarily are 15 to 1100 denier andfilling yarns 15 to 3300 denier. When warp yarns are used, they may be,e.g. 15 to 6600 denier. Normally, stitches will be 0.4 to 4 mm. apartalong the warp and about 1.13 to 3.57 mm. apart across the fabric.Typically, the sewn fabric weighs 2 to ounces per square yard.

The filling threads mentioned above are cast off the heddle hooks afterthey are caught up by loops of sewing threads which gather them intoclusters, separated by spaces where the sewing thread passes through thefabric. At the edges of the fabric, the filling threads reversedirection and form loops extending beyond the last chain of stitches.Alternately, these edge loops are severed from the body of the fabric,in the hope of producing a neat edge. Prior to the present invention,when interlocking chain stitching was used, a neat edge was not possiblebecause of the loose sewing thread in the last stitch chain, asdescribed above.

Another type of loose filling material which can be used in this type offabric is a batting or non-woven fiber web. This is a web of looselyarrayed fibers of any of the types previously mentioned, extending moreor less randomly in various directions. Webs of this type may be formedby depositing atmospherically suspended fibers onto a moving screen, forexample by suction applied through the screen. Webs also can be producedby carding a picker lap, and thickness can be increased by cross-layinga web in known manner. Strictly speaking, a batting or the like cannotbe described as loose filling because the fibers are arranged more orless randomly in all directions. However, since a portion of the fiberswill be more or less transverse or oblique to the loop chains,especially when derived from a cross-layed carded web, it can beconsidered to comprise loose filling for purposes of the presentinvention. Depending upon the relationship between the fibers, fabricsof this type may exhibit a tendency for the filling to be gathered intoclusters by the sewing thread.

The invention will be better understood from the following detaileddescription of preferred embodiments, reference being made to thedrawing, in which:

FIG. 1 is a perspective view of the portion of the apparatus where loopchains are formed;

FIG. 2 is a plan view of the apparatus, some parts being omitted forclarity;

FIG. 3 is a cross-section of a portion of the apparatus;

FIG. 4 is a cross-section similar to FIG. 3 but showing the parts afterthey have moved in the next step of operation;

FIG. 5 is a schematic drawing showing the path of movement of a threadguide about adjacent sewing needles;

FIG. 6 is a view of the fabric on greatly enlarged scale, the fillingmaterial being omitted for clarity;

FIG. 7 is a perspective view, on greatly enlarged scale, of a portion ofthe apparatus but with some parts omitted for clarity showing sewingthread being layed into the sewing needles;

FIG. 8 is a view similar to FIG. 7, but at a subsequent stage in theoperation;

FIG. 9 is a plan view, partially in section, of a portion of theapparatus showing the means for operating the needles and thread guides;and

FIG. 10 is a cross-section along lines 1010 of FIG. 9.

As seen in FIG. 6, the sewing thread in the fabric is formed intointerlocked chain stitching substantially along the warp or machinedirection. Each sewing thread 1 is formed into a plurality of loops 2spaced along the length of the fabric, each loop passing through thefabric. The loops are formed into parallel chains, but each chain isformed from two threads which alternately are formed into stitches ofadjacent chains. For example, one chain of loops, designated 3 in thedrawing, is formed from two threads 4 and 5. A first loop 6 is formedfrom thread 4, the next loop 7 is formed from thread 5 and the next loop8 is formed again from thread 4, etc. Thread 4 also is formed into loops9 in the chain 10 on one side of chain 3, alongside loop 7 and otherloops in chain 3 which are formed from thread 5. Similarly, thread 5also is formed into loops 11 in a chain 12 on the other side of chain 3,alongside loops 6 and 8 in chain 3. The arrangement is such that eachsewing thread is interlocked with two others in adjacent stitch lines sothat, if a thread breaks, it will not pull out a succession of stitchesas it would if each chain were formed from a single thread. 7

The formation of this chain stitching is illustrated in FIGS. 3 and 4. Aneedle 20 is provided which has a point 21 at one end and a hook 22adjacent the end. There is a groove 23 in the upper surface of theneedle in which slides part of a bent wire latch 24. The needle ismounted for horizontal reciprocating motion.

A web 25 moves downwardly across the path of the needle, and as theneedle reciprocates it alternately pierces and is withdrawn from theweb, the web being advanced downwardly while the needle is withdrawn.

A thread guide 26 is provided to insert the sewing thread 27 into thehook 22 when the needle extends through the web. As can be seen bycomparing FIGS. 3 and 4, the thread guide moves up alongside the needle,across it and down on the opposite side, laying the thread in the book22 as it moves across. Then the needle is retracted and the latch 24moves across the hook. At the same time, the web 25 moves down past theneedle. As the needle moves forward to receive sewing thread again,

the thread previously placed in the hook slides back onto the shank ofthe needle as seen at 28 to form a loop 29. When the needle retractsagain and the latch 24 closes, the loop 29 slides forward toward the tipof the needle, pushed if necessary by the upright portion of latch 24.Since the hook 22 is closed by the latch, the loop 29 slides over thehook and is cast off the point 21 of the needle. At the same time, thethread in the hook is pulled through loop 29.

The thread guide 26 is mounted to alternately move up and across twoneedles, designated 201 and 202 in FIG. 5. Therefore, it describes afigure eight path 30.

The problem which the present invention avoids can best be understoodfrom FIG. 5. Assuming that a needle 201 is the needle at the edge of thefabric being manufactured, one thread guide designated 261 (see FIG. 1)describes the path 30 and alternately lays thread into needles 201 and202. An adjacent thread guide 262 alternately lays thread in needle 202and the needle 203 which is adjacent to needle 202. Thus, when thethread guide 261 is laying thread into needle 201, thread guide 262 islaying thread into needle 202. When the next stitch is formed, threadguides 261 and 262 lay thread into needles 202 and 203, respectively.But no thread is laid into needle 201. Therefore, when needle 201 isretracted, the loop on its shank is cast off, but there is no thread inits hook to pull through the loop. Therefore, that loop is left loose.

The present invention provides means for pulling out that loop beforeanother loop is formed by needle 201, so that the thread is pulled tightbehind the line of loops formed by needle 202. As seen in FIGS. 1, 7 and8, this is accomplished by a resilient thread guide 31 over which passesthe thread supplied to the thread guide 261. The resilient thread guide31 is a piece of spring steel, firmly mounted at one end to the frame ofthe apparatus, for example by a block 32. The free end of the resilientthread guide 31 is bent to form a kind of hook 33 over which the sewingthread passes. There also is asingle loop 34 formed in the wire betweenits ends, to give it controlled resilience. The resilience of the guide31 is sufliciently weak to be overcome by thread tension when a loop isformed by needle 201, but sufiiciently strong to pull out a loose loopof thread after it is cast off the needle 201. Thus, when a loop isformed on needle 201, the thread pulls the guide 31 down, and when theloop is cast off and is loose, the guide 31 elevates and pulls out theloose loop. This sequence is illustrated diagrammatically in FIGS. 7 and8.

For rapid machine operation, it is advisable to use circular eccentriccams for actuating the needles and the thread guides. As shown in FIG.9, a needle bar carrying the needles 20 is actuated by a connecting rod41 extending from an eccentric rod 42 linked by a strap 43 of aneccentric cam 44 which. is rotated by the motor-driven shaft 45supported by a housing 46. Similarly, the reciprocating movement of thelatches 24 required for closing the hooks of the needles is obtained bymeans of an eccentric cam 47 cooperating with a strap 48 actuating,through an eccentric rod 49, a connecting rod 50 that actuates thebrackets to which the latches 24 are attached through a cam. The holdersof the thread guides 26 are fastened to a guide bar 51 which, by meansof suitably attached lever arms 52, is fixedly mounted on a shaft 53.This shaft, being rotatably mounted within bearings 54, is adapted toslide longitudinally back and forth and carries a short lever 55.

Lever 55 is connected with a coupling rod 56 linked to an eccentric rod57. Rod 57 with its strap 58 encloses the eccentric cam 59 which, bymeans of an intermediate connecting rod 60, moves the thread guides upand down. Aside from this reciprocating movement, the thread guides mustundergo an axially transverse back and forth movement in order to insertthreads into the hooks of the needles and to alternate between needles.For this purpose, the thread guides 26 and the shaft 53 carrying thesame are operated to perform one complete back and forth movement whilethe needles are moved twice in and out. To accomplish this, a pinion 61keyed to the shaft 45 engages a spur wheel 62 of twice its size.Consequently, the spur wheel rotates at half of the speed of the shaft45.

Spur wheel 62 is fixedly connected with an eccentric cam 63 whose strapmember 64 is linked by an eccentric rod 65 to a connecting rod 66axially slidable in a bearing 67. When in operation, the rod 66 and itslinkage 68 impart axial reciprocation to the shaft 53 by actuating anangle lever 69 rotatably mounted to a pivot 70. The tension spring 71fastened about the shaft 53, between one of the bearings 54 and theadjacent lever arm 52 of the guide bar 51 aids the axially oscillatingmovement by forcing the shaft against an adjusting screw 72 connectingthe free end of angle lever 69 to that of the shaft 53.

The filling yarn supply is illustrated in FIG. 2. For simplicity, asingle yarn is shown, indicated by the numeral 80. At opposite sides ofthe apparatus, there are chains 81 and 82, each trained around sprocketwheels and driven by a motor, not shown. On each of the chains 81 and 82there are a plurality of upright heddle hooks 83 around which the yarnis wound. Filling yarn is laid in place by a yarn guide mounted on amobile carriage 84 which is traversed back and forth above the chains 81and 82. The arrangement is such that as the carriage moves a bit pastthe hooks on one side of the chains, the chain moves and the yarn isturned around one or more hooks. Then the carriage moves in the oppositedirection across to the other chain and past that chain so that theprocedure is repeated.

In actual practice, the carriage 84 carries several yarn guides and aplurality of yarn ends is laid down as superimposed layers, each layerbeing at an angle to the layer next to it. The filling yarn remains inthis position until loops are formed by the sewing operation, and thefilling is cast off the chains 81 and 82. Then the filling takes theforms of generally parallel clusters of yarn separated by spaces atsewing thread stitch insertion points.

In lieu of this type of filling yarns, various types of nonwovenmaterials may be used. They may be supplied from a beam and carried tothe sewing needles by the chains 81 and 82.

In some cases, the fabric may use warp yarn which is simply laid underthe sewing thread and against the filling. The warp yarn is supplieddownwardly against the filling through a yarn guide 91 as seen in FIG.1.

A special arrangement must be provided for supplying the sewing thread.In the conventional machine described previously, a single sewing yarnpackage supplies a plurality of ends, one for each thread guide.However, in using the present invention, this is not possible becausethe outermost sewing thread forms only one half as many loops as threadsforming loops at the interior of the fabric. To maintain proper tension,it is necessary that the outermost sewing thread not unwind from thepackage at the same rate as other threads. Therefore, in accordance withthe present invention, the outermost sewing thread is supplied from aseparate package, capable of unwinding at a different speed from threadused at the interior of the package. The arrangement is illustrated inFIG. 2 in which three sewing yarn packages are indicated by the numerals95, 96 and 97 on a beam 98. Sewing thread ends are supplied from thesepackages through appropriate thread guides and tensioning devices, notshown, to the thread guides 26 which lay them into the sewing needles20. The packages 96 and 97 each supply one end to the outermost threadguides 20 while the package 95 supplies a plurality of ends to the otherthread guides 20. All three packages are mounted on the beam 98 to becapable of rotation at separate speeds. If the package 95 is mounted tothe beam and the beam is rotatable, the packages 96 and 97 must bemounted on the beam with bearings to rotate independently. If thepackages are unwound by a power drive, rather than through threadtension, obviously packages 96 and 97 must be driven at slower speedthan the package 95, i.e. at about half speed. Various changes may bemade in detail of construction and mode of operation without departingfrom the scope of the invention, as defined in the appended claims.

What is claimed is: 1. In a warp knitting apparatus for producingtextile fabric, said apparatus comprising a plurality of knittingneedles in a row, means for simultaneously extending and simultaneouslywithdrawing said needles, said needles having means for holding sewingthreads supplied to them when they are extended so that the sewingthreads are drawn through said fabric as said needles are withdrawn andthereby form loops, said loops being received on the shanks of saidneedles when next extended and cast off said needles when they are nextwithdrawn and a plurality of sewing thread guides in a row adjacent saidrow of needles to supply sewing threads to said needles when extended,each guide supplying a sewing thread alternately to one and then theother of a pair of adjacent needles during alternate extensions of therow of needles, the withdrawing needles pulling a sewing thread throughsubstantially all of said loops as they are cast off, but the sewingthread supplied by the thread guide at one end of said row being leftloose in alternate loops without a sewing thread therethrough;

the improvement comprising resilient thread guide means in contact withthe sewing thread supplied to said thread guide at one end of said row,said thread guide means including resilient means such that the part ofthe thread guide means contacted by said sewing thread is displaced whensaid sewing thread is pulled by a withdrawing needle but recovers itsundisplaeed position when a loose loop is cast off, pulling out saidloop and drawing the sewing thread substantially taut.

2. In a -warp knitting apparatus for producing a textile fabric having afilling comprising a plurality of loose filling yarns or fibers and aplurality of loops of chain threads along one side of said fillinggenerally perpendicular to said loose filling yarns or fibers, withsewing thread connecting between loops extending through said fillingand along the other side of said filling,

said apparatus comprising a plurality of knitting needles in a row,means for moving said filling past said needles, means forsimultaneously inserting and simultaneously withdrawing said needlesthrough said filling, said needles having means for holding sewingthreads supplied to them they are inserted in the filling so that thesewing thread is drawn through said filling as said needles arewithdrawn, thereby forming loops, said loops being received on theshanks of said needles when the needles are again inserted through saidfilling and cast off said needles when the needles are again withdrawn,

and a plurality of sewing thread guides in a row adjacent said row ofneedles to supply sewing threads to said needles when inserted throughsaid filling, each guide supplying a sewing thread alternately to oneand then the other of a pair of adjacent needles during alternateinsertions of the row of needles,

8 the withdrawing needles pulling sewing threads through substantiallyall of said loops as they are cast off said shanks, but the sewingthread supplied by the thread guide at one end of said row being leftloose in alternate loops without a sewing thread therethrough;

the improvement comprising thread guide means in contact with the sewingthread supplied to said thread guide at one end of said row, said threadguide means including resilient means so that the part of the threadguide means contacted by said sewing thread is displaced when saidsewing thread is pulled through said fabric by a needle but recovers itsundisplaeed position when a loose loop is cast off, pulling out saidloop and drawing the sewing thread substantially taut against said otherside of said filling.

3. A warp knitting apparatus as set forth in claim 2 in which saidthread guide means comprises a spring biased thread guide.

4. A warp knitting apparatus as set forth in claim 2 in which saidthread guide means comprises an elongated spring having an aperturethrough which said sewing thread passes.

5. In a method of producing a textile fabric having a filling comprisingloose filling yarns or fibers, and a plurality of chains of loops ofsewing thread along one side of said filling generally perpendicular tosaid loose filling yarns or fibers with sewing thread connecting betweenloops extendi-ng through said loops and along the other side of saidfilling,

said method comprising inserting a row of needles through said filling,supplying sewing threads to each of said needles, withdrawing saidneedles from said filling, thereby drawing said sewing threads throughsaid fabric and forming them into loops, advancing said filling pastsaid needles, and repeatedly reinserting and withdrawing said needlesthrough said filling at spaced points along the filling as it isadvanced, the sewing threads each being supplied alternately to adjacentneedles in said row during successive needle insertions so that eachthread forms alternate loops into adjacent chains, the loops being castofi? said needles when the needles are withdrawn, pulling other loopsthrough substantially all of the cast oif loops, as they are cast off,but the loops formed by the last needle in said row being left loose asthey are cast off;

the improvement which comprises pulling the sewing thread supplied tothe pair of adjacent needles at the end of said row, after a loose loophas been cast off, so as to pull out said loose loop and draw its threadsubstantially taut against said other side of said filling, before saidlast needle in said row forms another loop.

References Cited UNITED STATES PATENTS 2,442,796 6/1948 Young 66863,262,287 7/1966 Woodcock 66--90 3,274,805 9/1966 Duhl 6684 2,365,9189/1968 Hughes 6685 RONALD FELDBAUM, Primary Examiner

1. IN A WARP KNITTING APPARATUS FOR PRODUCING TEXTILE FABRIC, ANDAPPARATUS COMPRISING A PLURALITY OF KNITTING NEEDLES IN A ROW, MEANS FORSIMULTANEOUSLY EXTENDING AND SIMULTANEOUSLY WITHDRAWING SAID NEEDLES,SAID NEEDLES HAVING MEANS FOR HOLDING SEWING THREADS, SAID NEEDLESS WHENTHEY ARE EXTENDED SO THAT THE SEWING THREADS ARE DRAWN THROUGH SAIDFABRIC AS SAID NEEDLES ARE WITHDRAWN AND THEREBY FORM LOOPS, SAID LOOPSBEING RECEIVED ON THE SHANKS OF SAID NEEDLES WHEN NEXT EXTENDED AND CASEOFF SAID NEEDLES WHEN THEY ARE NEXT WITHDRAWN AND A PLURALITY OF SEWINGTHREAD GUIDES IN A ROW ADJACENT SAID ROW OF NEEDLES TO SUPPLY SEWINGTHREADS TO SAID NEEDLES WHEN EXTENDED, EACH GUIDE SUPPLYING A SEWINGTHREAD ALTERNATELY TO ONE AND THEN THE OTHER OF A PAIR OF ADJACENTNEEDLES DURING ALTERNATE EXTENSIONS OF THE ROW OF NEEDLES, THEWITHDRAWING NEEDLES PULLING A SEWING THREAD THROUGH SUBSTANTIALLY ALL OFSAID LOOPS AS THEY ARE CAST OFF, BUT THE SEWING THREAD SUPPLIED BY THETHREAD GUIDE AT ONE END OF SAID ROW BEING LEFT LOOSE IN ALTERNATE LOOPSWITHOUT A SEWING THREAD THERETHROUGH; THE IMPROVEMENT COMPRISINGRESILIENT THREAD GUIDE MEANS IN CONTACT WITH THE SEWING THREAD SUPPLIEDTO SAID THREAD GUIDE AT ONE END OF SAID ROW, SAID THREAD GUIDE MEANSINCLUDING RESILIENT MEANS SUCH THAT THE PART OF THE THREAD GUIDE MEANSCONTACTED BY SAID SEWING THREAD IS DISPLACED WHEN SAID SEWING THREAD ISPULLED BY A WITHDRAWING NEEDLE BUT RECOVERS ITS UNDRISPLACED POSITIONWHEN A LOOSE LOOP IS CAST OFF, PULLING OUT SAID LOOP AND DRAWING THESEWING THREAD SUBSTANTIALLY TAUT.